This week in What's that Sound? we're taking a look at the pump organ, also known as the harmonium.
In Europe, early iterations of the harmonium came about as early as 1780, and as the instrument spread to the US, it peaked in popularity in the 19th and 20th centuries. Originally harmoniums were used in churches as a smaller and cheaper alternative to the pipe organ. They were stand-alone instruments with a foot pedal to control the bellows as both hands played the keys. It wasn't until the instrument was introduced in India that it became the handheld version that is most commonly used today (and illustrated here).
It wouldn't look like it from the outside, but the harmonium is actually a reed instrument. Air is pumped into the harmonium using external and internal (unseen) bellows. Opening and closing the stops determines which chambers the air is allowed to move through and which bank of reeds are activated. This distinguishes the "voice" of the instrument and can create the layered effect of the sound.
Fun Fact :: the phrase "pulling out all the stops" refers to organ stops. When all the stops are pulled out the organ plays all variations of that sound at once, thus being the loudest possible.
By the 1930s, with the development of the electric organ, the reign of the harmonium in the West was basically over. (Although its distant cousin, the accordion, continued to thrive.) But this instrument still remains extremely important in genres of Indian music and helps give it the distinct sound we recognize.
Watch as this 8 year old kid plays the children's song Sasa to Sasa and totally kills it:
Harmoniums still pop up in Western music. You can hear them featured in a number of songs by the Beatles, including We Can Work It Out and Being for the Benefit of Mr. Kite. More recently, Sharon Van Etten used a harmonium to layer beautifully with her vocals in her song D sharp G.
So what's that sound? Now you know!